A small wind turbine like this one may be coming soon to a roof near you.

They look a bit like attachments for a gigantic hand-held mixer. But at five meters (16 feet) tall and with a diameter of close to three meters, they are certainly too big for a kitchen cabinet. They would, however, definitely fit in backyards and city parks and on the roofs of houses and office buildings.

And if the German power company RWE has its way, there will soon be thousands of the funny-looking rotors installed in the coming months and years -- in Germany, in Europe and even in the US.

It is not, as one might be tempted to believe, a vast, futuristic art project. Rather, the odd-looking, twisting contraptions are the newest generation of high-tech wind turbines. In contrast to their cousins, these windmills are virtually silent, do not require long blades to catch the wind, and spin no matter which direction the wind is blowing. Even better, their modest size and weight mean they can easily be installed on rooftops -- and they can generate up to 10,000 kilowatt hours of electricity a year, enough to supply two low-energy homes, or a 20 person office, with power.

The rotors are produced in limited numbers by a company called Quiet Revolution located in Great Britain. Founded in 2005, the company has already managed to demonstrate that it may have vast potential. Late last year, the company produced its first rotors, and almost immediately began winning design and technical prizes.

Furthermore, the first model -- known as QR5 -- has been installed on a number of rooftops in England. There is one located on top of Kings College School in Wimbledon and an ever-growing number of high-rise buildings are likewise crowned by the apparatus. A large pub chain has begun installing them as well.

Indeed, the future looks so bright for Quiet Revolution that the German energy giant RWE recently bought a small stake in the company -- a move that was officially announced at a press conference on Monday in Essen, where RWE is based. The share is worth 7.5 million ($11 million).

Since the beginning of the year, Fritz Vahrenholt has been responsible for expanding RWE's presence in the renewable energy sector. Formerly the head of the wind turbine company Repower, Vahrenholt has also steered RWE into billions worth of investments in offshore wind parks and led RWE's construction of biomass facilities.

He has also kicked off a search for innovative new companies. "When I saw Quite Revolution," Vahrenholt says, "it was immediately clear to me that with this wind turbine, the dream of many people to have their own, decentralized power supply could be fulfilled -- even in places where the sun doesn't shine and where there is no power grid."

Still, he warns against getting too excited. "These turbines aren't going to change the overall energy mix," Vahrenholt says. The output is still too low and, at 30,000 per turbine, the price is still too high. Installation and maintenance costs make the mini-windmills even more expensive. For the moment, they are little more than a prestige or marketing installation for rich environmentalists.

But RWE's investment could change that. There are already ideas to replace the carbon-fiber material out of which the turbines are made with cheaper materials. There is also plenty of room for output to be boosted. Furthermore, should the gadgets prove workable, they could be mass-produced in a country where labor is cheaper. The cost per unit could fall dramatically -- assuming there is a demand.

But few doubt that there would be. Just a few days ago, New York Mayor Michael Bloomberg announced that he is interested in installing wind turbines on top of the city's buildings. "If rooftop wind can make it anywhere, this is a great city," he said. "We have a lot of tall buildings."